If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Guide me to bumping technique.

10-20-2012, 01:29 AM

Hi all,
Tried the bumping tech yesterday, the material is a broken car velg, anodized like a mirror, thickness about 5-6mm. I used Syncrowave 250DX, the settings are: 8LPM 100% Argon, 3/32 1,5% Lant tung, gas lens with cup #6, WP18, 150Amps, balance at 4 (balanced?), wiped with thinner (got no acetone here). I can get a puddle in about 2-3secs, it's a clean puddle.
The problem is when I dab the filler (4043) for the second time. The puddle will soon contaminated (looks skinny). No problem when first time dab. The cleaning area not seen.
The question is what did I do wrong? Is it normal not to have a cleaning area when bumping the anodized? Maybe the cup was to small? Amp not hi enough?
Any information and suggestion is greatly appreciated. Thank you all in advance.

Comment

Comment

Steph i am running a dynasty 350 i use 5356 rods on boat towers. I also run at about 200 to230 depending on the thickness. Bump get a puddle dab bump dab bump etc. The only differance is i use higher setting and a 5356 rod. Good luck

Comment

@gaby: you use 200-230amps on what thickness?
@cruizer: I didnt preheat because I can get a clean puddle in 2-3 seconds. Do I still need a preheat? Maybe I need to change a bigger cup?
@cruizer & portablewelder: whats your suggestion to clean it? I thought thinner will clean the oil and grease well. I didnt stainless brushed it because it looked very clean.

Thank you guys for spending time with me.

Comment

Dude.....if you are welding on a car wheel.....you need to give us a LOT more info.
Keeping the anodize pretty should be the absolute least of your worries.
This thread is pretty much useless without some sort of decent pics of what you are doing.

Comment

1 Must clean wheel with Stainless steel brush.
2 Must clean wheel with Stainless steel brush.
3 Must clean wheel with Stainless steel brush.
4 th hint is must clean wheel with Stainless Steel brush. Brush must not be used on anything but stainless Steel or problems happen.
( this is about how many times I had to learn before it sunk in.)

Comment

I run 200 -230 amps on my dynasty. Remember anodized aluminum is hard because the anodize acts or better yet is contamination. 200 amps should burn through that. I weld boat towers all day and it is not easy. God luck 1/8 - 1/4 is the size i use.

Comment

oops, my bad
I see you must be using a car wheel for practice!
Dirty cast underneath isn't the same as an extrusion that has been anodized tho.
You may get some halfway decent looking beads tho if it is a decent piece.
Pics would still help

Comment

@FusionKing: yes, I only practice, this is not a real weld. The wheel was badly broke and the owner has left it for more than 3 years in my shop, so I count it as a scrape and use it for practice. Without adding filler rod there's no contamination. The contamination only appears on second, third, and the next dab. I'll try upload a pic when I have free time.

@Go2building: yes, it's a pain thinner. Is denatured alcohol is 70% alcohol they used in medical/hospital??

@Mcostello:Few minutes before I weld the anodized, I tried to weld a cast alum, it's a 3" elbow with no problem. Laid a ..maybe 3" long beads. With the same thinner wipe and no stainless brushed. Or something I've missed here??